Since the beginning of the industrial revolution, United States and foreign crude oil refining and chemical companies have developed many useful petrochemical products. While these new products have provided solutions to many of the problems that have arisen during the advancement of industrialized society, the demands of industry for new and innovative petrochemical products have increasingly required development of more efficient means for handling and transporting both unrefined and refined petroleum products. Many of these means involve transporting products via pipeline, truck, ship, rail, or other methods to bulk storage facilities or end users. Unfortunately, in handling these petroleum and petrochemical products, there have been many instances of their release into the environment.
Release of petroleum or petrochemical products into the environment can have far reaching affects, ranging from minor innocuous impact to total devastation depending upon the particular contaminant released, the quantity released, proximity to human populations, the sensitivity of the area and many other factors. Recognizing the concerns associated with this growing industry, the United States Congress enacted the National Environmental Policy Act ("NEPA") of 1969 followed by establishment of the Environmental Protection Agency ("EPA"). Prior to this legislation and for several years afterward, however, state and federal agencies failed to aggressively pursue environmental violators, assuming the largely unreported releases to be minor, the public pressure of the environmental movement having not yet reached maturity.
As a result of this environmental disinterest, little is known about soil and groundwater remediation technology prior to the 1980's. As public pressure began to mount, however, numerous environmental equipment manufacturing companies began to produce equipment designed to pump oil or other phase-separated hydrocarbons released onto surface water or into groundwater. Early equipment designs included the Oil Recovery Services ("ORS") trademark "FILTER SCAVENGER" floating disk which utilized an electrical pump to transfer recovered fluids to a holding tank. Although improvements were made to the system, including utilization of a hydrophobic screen to repel water and allow only oil to enter the system, it remained limited to low flow rates.
Soon after introduction of this early system, the market was flooded with down-hole oil pump systems. These systems were designed to pump oil to an above ground reservoir for storage. Pneumatic pump systems were designed to then pump the total fluids (oil and water) to an oil-water separator located on the surface. These systems were soon coupled with submersible groundwater pumps in an effort to increase oil recovery, with some success.
Contaminated soil, on the other hand, was primarily addressed in the 1980's by excavation and removal, to the extent possible. When deeper soils were impacted by a hydrocarbon release and could not be effectively reached by excavation, the soils remained in place. But then in the mid-1980's, a new and highly effective soil remediation process called vacuum extraction was developed. Vacuum extraction removes the volatile organic compounds from the soil by the application of negative pressure on a well which is screened through the hydrocarbon impacted soil.
Soon after their advent, vacuum extraction (for soil remediation) was combined with oil pumps and down-hole submersible pumps (for groundwater remediation) in an effort to expedite remediation. Vacuum extraction systems were typically connected to dedicated vacuum extraction wells as were oil pumps with groundwater submersible pumps. These systems proved highly effective in soils which exhibited high transmissivity (sand, gravel and other permeable formations) where fairly high flow rates could be achieved. However, in soils with low transmissivity, this combined approach failed to produce favorable results due to gravitational limitations and long-term residual impact to groundwater.
Finally, a dual phase vacuum extraction technique was introduced wherein a liquid ring vacuum pump was utilized to recover groundwater while simultaneously extracting vapors from a formation. This type of vacuum pump system uses groundwater or tap water to create a vacuum within the pump. Groundwater, with dissolved hydrocarbon compounds, and vapor pass directly through the liquid ring pump and into a holding tank prior to transfer to a treatment system. While this type of pump overcame the limitations prevalent to most prior systems, this technology is limited to sites which have soil contamination coupled with dissolved hydrocarbon contamination in groundwater. A dual-phase extraction system is not suitable for the recovery of phase-separated hydrocarbons (free product and oil) on the groundwater because all fluids pass directly through the pump impeller which causes an inseparable emulsion due to shearing of the fluids. The only modifications proposed to this system have required introduction of separate down-hole pumps, greatly increasing capital equipment and project lifetime maintenance costs.
Prior to the introduction of the present invention, there has been introduced no method of recovering phase separated hydrocarbons, groundwater, and vapors from soil which exhibits low transmissivity without causing emulsion and without using separate down-hole pumps. Prior existing technology will either create an inseparable emulsion due to shearing of the fluids, or require down-hole pumps in each well in conjunction with a high vacuum pump system.
Further, prior existing liquid ring vacuum pump systems require either tap water, groundwater or a combination of both in order to create the necessary vacuum pump seal. At remote sites, where tap water is relatively unavailable and groundwater must be used, the total dissolved solid content of the groundwater typically results in high maintenance costs for the liquid ring pump.
It is a primary object of the present invention to provide a high-vacuum groundwater and soil remediation system capable of recovering phase separated hydrocarbons, groundwater and/or vapors from a single well, in soils of high or low transmissivity and without emulsification of the free product.
It is a further object of the present invention to provide a high-vacuum groundwater and soil remediation system having a self-contained cooling seal water system, operable without need for a continuous source of tap water and impervious to maintenance problems as have plagued prior art systems.
It is yet another object of the present system to provide a high-vacuum groundwater and soil remediation system which is self-contained and portable for rapid response to a variety of locations.